Migraine Headache

Definition

Migraine is a type of headache marked by severe head pain lasting several hours or more.

Description

A migraine is an intense, often debilitating type of headache. Migraines affect as many as 24 million people in the United States, and are responsible for approximately $17 billion in lost work, poor job performance, and direct medical costs. Approximately 18% of women and 6% of men experience at least one migraine attack per year. More than three million women and one million men have one or more severe headaches every month. Migraines often begin in adolescence, and are uncommon after age 60.

Two types of migraine are recognized. Eighty percent of migraine sufferers experience migraine without aura, formerly called common migraine. In migraine with aura, formerly called classic migraine, pain is preceded or accompanied by visual or other sensory disturbances, including hallucinations, partial obstruction of the visual field, numbness or tingling, or a feeling of heaviness. Symptoms are often more prominent on one side of the body, and may begin as early as 72 hours before the onset of pain.

Causes and symptoms

Causes

The physiological basis of migraine has proved difficult to uncover. Genetics appear to play a part for many, but not all, people with migraine. There are many potential triggers for a migraine attack, and discovering one's own set of triggers is often the key to prevention.

PHYSIOLOGY. The most widely accepted hypothesis suggests that a migraine attack is precipitated when pain-sensing nerve cells in the brain (called nociceptors) release chemicals called neuropeptides. Another brain chemical, a neurotransmitter called substance P, increases the pain sensitivity of nearby nociceptors. Neuropeptides act on the smooth muscle that surrounds cranial blood vessels. This smooth muscle regulates blood flow in the brain by relaxing or contracting, which dilates (enlarges) or constricts (narrows) the enclosed blood vessels.

At the onset of a migraine headache, neuropeptides are thought to cause muscle relaxation, which allows vessel dilation and increased blood flow. Other neuropeptides increase the leakiness of cranial vessels, allowing fluid leak, and promote inflammation and tissue swelling. The pain of migraine is thought to result from this combination of increased pain sensitivity, tissue and vessel swelling, and inflammation. The aura seen during a migraine may be related to constriction in the blood vessels that dilate in the headache phase.

GENETICS. Susceptibility to migraine may be inherited. A child of a migraine sufferer has as much as a 50% chance of developing migraine. If both parents are affected, the probability rises to 70%. However, the gene or genes responsible have not been identified, and many cases of migraine have no obvious familial basis. It is likely that whatever genes are involved set the stage for migraine, and that full development requires environmental influences as well.

TRIGGERS. A wide variety of foods, drugs, environmental cues, and personal events are known to trigger migraines. It is not known how most triggers set off the events of migraine, nor why individual migraine sufferers are affected by particular triggers but not others.

Common food triggers include:

• aged cheese
• alcohol, especially red wine
• caffeine and caffeine withdrawal
• chocolate
• intensely sweet foods
• dairy products
• fermented or pickled foods
• citrus fruits
• nuts
• aspartame
• processed foods, especially those containing nitrites, sulfites, or monosodium glutamate (MSG)

Environmental and event-related triggers include:

• stress or time pressure
• menstrual periods, menopause
• sleep changes or disturbances, oversleeping
• prolonged overexertion or uncomfortable posture
• hunger or fasting
• odors, smoke, or perfume
• strong glare or flashing lights

Drugs that may trigger migraine include:

• oral contraceptives
• estrogen replacement therapy
• nitrates, often found in cured meats such as bacon and ham
• theophylline, an asthma drug
• reserpine, a tranquilizer
• nifedipine, a calcium channel blocker
• indomethacin, an NSAID
• cimetidine, a histamine H₂ antagonist
• decongestant overuse
• analgesic overuse
• benzodiazepine (a type of tranquilizer) withdrawal

Symptoms

Migraine without aura may be preceded by elevations in mood or energy level for up to 24 hours before the attack. Other premigraine symptoms may include fatigue, depression, and excessive yawning.

Aura most often begins with shimmering, jagged arcs of white or colored light progressing through the visual field over the course of 10-20 minutes. This may be preceded or replaced by dark areas or other visual disturbances. Numbness and tingling is common, especially of the face and hands. These sensations may spread, and may be accompanied by a sensation of weakness or heaviness in the affected limb.

The pain of migraine is often present only on one side of the head, although it may involve both, or switch sides during attacks. The pain is usually throbbing, and may range from mild to incapacitating. It is often accompanied by nausea or vomiting, painful sensitivity to light (photophobia) and sound (phonophobia), and intolerance of food or odors. Blurred vision is common.

Migraine pain tends to intensify over the first 30 minutes to several hours, and may last from several hours to a day or longer. Afterward, the affected person is usually weary, and sensitive to sudden head movements.

Diagnosis

Migraine is diagnosed by a careful medical history. Lab tests and imaging studies such as computed tomography (CT) or magnetic resonance imaging (MRI) scans have not been useful for identifying migraine. However, for some patients, those tests may be needed to rule out a brain tumor or other structural causes of migraine headache.

Treatment

Once a migraine begins, the person will usually seek out a dark, quiet room to lessen painful stimuli. Several drugs may be used to reduce the pain and severity of the attack, and many people with migraines learn to prevent attacks altogether by recognizing and avoiding their triggers.

Nonsteroidal anti-inflammatory drugs (NSAIDs) are helpful for early and mild headache. NSAIDs include acetaminophen, ibuprofen, naproxen, and others. A recent study concluded that a combination of acetaminophen, aspirin, and caffeine could effectively relieve symptoms for many migraine patients. One such over-the-counter preparation is Excedrin Migraine.

More severe or unresponsive attacks may be treated with drugs that act on serotonin receptors in the smooth muscle surrounding cranial blood vessels. Serotonin, also known as 5-hydroxytryptamine, constricts these vessels, relieving migraine pain. Drugs that mimic serotonin and bind to these receptors have the same effect. The oldest of them is ergotamine, a derivative of a common grain fungus. Ergotamine and dihydroergotamine are used for both acute relief and preventive treatment. Derivatives with fewer side effects have come onto the market in the past decade, including sumatriptan (Imitrex). Some of these drugs are available as nasal sprays, intramuscular injections, or rectal suppositories for patients in whom vomiting precludes oral administration. Other drugs used for acute attacks include meperidine (Demerol) and metoclopramide (Reglan).

Continued use of some antimigraine drugs can lead to "rebound headache," marked by frequent or chronic headaches, especially in the early morning hours. This can be avoided by using antimigraine drugs under a health care provider's supervision, with the minimum dose necessary to treat symptoms. Patients with frequent migraines may need preventive therapy.

Alternative treatments are aimed at prevention. Since migraines are often linked with food allergies or intolerances, identifying and eliminating the offending food or foods can decrease the frequency of migraines and/or alleviate these headaches altogether. Herbal therapy with feverfew (Chrysanthemum parthenium) may lessen the frequency of attacks. Learning to increase the flow of blood to the extremities through biofeedback training may allow a patient to prevent some of the vascular changes once a migraine begins. Relaxation using focused breathing techniques can also be useful. During a migraine, keep the lights low; put the feet in a tub of hot water and place a cold cloth on the occipital region (the back of the head). This draws the blood to the feet and decreases the pressure in the head.

Prognosis

Most people with migraines can bring their attacks under control by recognizing and avoiding their triggers, and by using the appropriate drugs when migraines occur. There are, unfortunately, some people with severe migraines that do not respond to either preventive or drug therapy. Migraines usually wane in intensity after age 60.

Health care team roles

The advanced practice nurse (APN) can play a pivotal role in helping patients control migraine symptoms. One of the most important screening questions for a patient with a headache is "Do you think that this is the worst headache you have ever had?" If the answer is yes, a more thorough diagnostic work up is justified in order to rule out any tumor or brain bleed. Imaging studies, like CT and/or MRI scanning, which are performed by a radiologist technician, should be considered.

The APN must recognize that many people with migraines are underdiagnosed and unhappy with the practitioner's treatment plan. Knowing this will help the APN focus on both quick pain relief methods and complementary therapies.

The registered nurse (RN) and licensed practical nurse (LPN) can also contribute to a patient's successful migraine management by reinforcing the concept of rapid medication administration at the initial onset of migraine symptoms.

Patient education

The importance of teaching patients about their migraine medications and any potential side effects cannot be overstated. Explaining the expected time frame for relief before administering the next medication is helpful. Nurses can also advise patients about nonpharmacological interventions that may also be beneficial for migraine sufferers. Finally, the RN or LPN can demonstrate breathing relaxation techniques for patient to reinforce their proper use and understanding.

Prevention

The frequency of migraine may be lessened by avoiding triggers. It is useful to keep a headache journal, recording the particulars and noting possible triggers for each attack. Specific measures which may help include:

• eating at regular times, and not skipping meals
• reducing the use of caffeine and pain relievers
• restricting physical exertion, especially on hot days
• keeping regular sleep hours, but not oversleeping
• managing time to avoid stress at work and home

Some drugs can be used for migraine prevention, including specific members of these drug classes:

• beta blockers
• tricyclicantidepressants
• calcium channel blockers
• anticonvulsants
• fluoxetine (Prozac)
• monoamine oxidase inhibitors (MAOIs)
• serotonin antagonists

For most patients, preventive drug therapy is not an appropriate option, since it requires continued use of powerful drugs. However, for women whose migraines coincide with their menstrual periods, limited preventive treatment may be effective. Since these drugs are appropriate for patients with other medical conditions, the decision to prescribe them for migraine may be influenced by expected benefit elsewhere.

KEY TERMS

Migraine— A type of headache marked by severe head pain lasting several hours or more.

Neuropeptide— A peptide (chemical derived from protein) that affects nerves and their functions. Endorphins and enkephalins are neuropeptides.

Neurotransmitter— Chemical produced by nerve cells that sends an impulse across a synapse to a muscle, organ, or another nerve cell. Norepinephrine and acetylcholine are types of neurotransmitters.

Nociceptors— Nerve cells in the brain that are responsible for the sensation of pain.

Phonophobia— Sensitivity to sound.

Photophobia— Sensitivity to light.

Resources

PERIODICALS

Clinch, C. Randall. "Evaluation of Acute Headaches in Adults." American Family Physician 63 (February, 2001): 685-692.

Kunkel, Robert. "Managing Primary Headache Syndromes." Patient Care 34 (January, 2000): 100 ff.

Lipton, Richard B. "Sumatriptan for the Range of Headaches in Migraine Sufferers: Results of the Spectrum Study." Headache 40 (2000): 783-791.

Scholz, Mary. "Treatment Options for Acute Migraine." RN 63 (October, 2000): 99.

OTHER

American Medical Association. Journal of the American Medical Association: Migraine Information Center. ?http://www.ama-assn.org/special/migraine?.

Matchar, David B., Douglas C. McCrory, and Rebecca N. Gray. "Toward Evidence-Based Management of Migraines." ?http://jama.ama-assn.org/issues/v284n20/ffull/jed00081.html?. (April 27, 2001).